Delay arming, self-destroying and point detonating fuze device



Aprll 30, 1957 K. BAKER 2,790,390

- DELAY ARMING, SELF DESTROYING AND I POINT 01mm UZE nsvxcs Fi. April 1952 29. E I8 '3 M 34 7 I F I G.4. INVENTOR K. BAKER flaw \QAM. n-JM ATTORNEYS United States Patent DELAY ARMING, SELF-DESTRQYING AND ronvr DETONATlNG FUZE' DEVICE Kenneth L. Baker, Gollege Park, Mda, assignor to the United States of Americans represented by the Secrey f. t v

ApplicationApril-29, 1952, Serial No. 285,041

3 Glaims. ((31. 102-71) (Granted under *Ijfitle 35, U. S Code (1952), see. 266) The invention described herein may be manufactured and; used by or for the Government of the United States of America for governmental purposes without the payrnent of any. royalties thereon or therefor.

This invention relates to a fuze and more particularly to a point detonating and self destroying fuze for use in an ordnance missile such, for example, as a three inch type projectile.

Furthermore, the invention provides a new and improved fuze for a projectile. wherein means are provided for delaying the arming of the. fuze until the projectile has been fired from, a gun. andtraveled a predetermined distance beyond the muzzle thereof and thus 'bore. safety is insured, and in, which means are provided for exploding the projectile upon, impact thereof with a. target such, for example, as an aircraft in flight or when the spin of the projectilehas decreased to a predetermined value.

Heretofore, delayed arming and self destructing devices consisting of a multiplicity of intricate parts such, for example, as clockwork; mechanisms, cocked helical springs and numerous centrifugal actuated levers and detents. Such. complicated device's are costly and, consid erable time is consumed duringproduction thereof due, not only to the multiplicity of their intricate parts, but also. to the necessity of specially trained workers who must spend considerable time assembling such intricate partsan d thereafter testing the assembled devices to determine whether the devicev is in, proper working order. Heretofore, such fuzes required two Separate and independentme chanisms for causing delayed arming and. self destruction of the-projectile. Furthermore, such mechanisms involve. considerable cost during production and aleoSconsume considerable space within the fuzev casing which otherwise could. be used for additional explosives, thereby reducing the'potency. of such projectiles In view ofthe foregoing, the device of the present invention is constructed in. such a manner as to comprise a minimum number of simplepartswhich may be readily assembled by. unskilled. workers in a comparatively short periodof timeand which is small in size and devoid of intricate clockwork mechanisms and centrifugal actuated levers and detents. Furthermore, due to the size and compactness of the device additional space is made available. for increasing the quantity of explosive materials either in the fuze or projectile as the casemay be whereupon the potency of the'fuze or projectile is increased and in which delayed arming and self destruction features are incorporated in a single mechanism or unit.

v The device of the prescnt invention consists of a Negator spring such, for example, as the type manufactured by the Hunter Spring Co, of Lansdale, Pennsylvania, the springbeing disposed around an inertial rotor, one end of the'spring is secured to the inertial rotor; the other end thereof being secured to thefuze casing. The spring is disposedwithin a recess. formed in the fuze casing, the diameter ofrthefwall' defining the recess being considerablyflarger than the diameter ofthe spring when the spring is in its normally wound 'condition. Bythis arrangement. suflicient, room is. provided. to permit outward movement ofthe spring as. the spring is unwound in response to, centrifugal force as. the projectile. spins. along its trajectory and thus. during such movement of the spring sufficient energy is stored therein to cause the spring to assume its original condition when the rateof spin. of the. projectile reaches, a relatively low value.

As the projectile is fired from a gun, angular acceleration tends to tighten the spring around: the inertia weight and also tends to rotate the inertial weight in a. direction to prevent arming of the fuze and thus in respons to such action bore safety is insured, Furthermore, initial ac.- celeration also tends to maintain the firing pin. in lock: ing engagement with the arming rotor as the projectile is fired and travels through the barrel of the gun. However, when the speed of rotation of the projectile reaches a predetermined value centrifugal force moves the convolutions of the spring outwardly and thus. causing the spring to unwind. As the spring u-nwinds the inertial rotor is rotated a predetermined amount depending upon the number of convolutions of the spring, the ratio of the coil diameter and the diameter of the aforesaid recess. Furthermore, in response to the movement of the coil spring by reason of; the outer and inner convolutions thereof being securedto the casing and rotor respectively, rotatiye, movement is transmitted to the rotor, such movement being sufficient to move the firing pin to a firing position and concurrently therewith releases the arming rotor for rotation to an armed position in response to centrifugal force and thus the fuze is armed.

Upon impact of the projectile with the target the firing pin is forcibly driven into firing engagement with the detonator whereupon the bursting charge is initiated and the projectile exploded. The aforesaid spring arrangement maintains, the inertial weight in an initial safe position until the speed of rotation of the Proje t le has rea h pr d rmined value. Fur: thermore, the spring functions tocause self destruction of the projectile when the speed of rotation of the projectile has decreased to a relatively low value.

When the speed of rotation of the projectile is sub.- stantially reduced theenergy stored within thespringin response to theunwinding and outward movement of the convolutions thereof overcomes the centrifugal force.- acting thereon and thus the spring assumesits original con-. dition and concurrently therewith, and actuated thereby the-inertial rotor is moved toits original position. Such movement of the inertial rotor under the influence of the spring moves the firing pin into firing engagement with the sensitive deton'ator which initiatesithebursting charge andlexplodes the pr jfictile.

One 'of the objects of the present invention is the provision of a new and improved fuze for use in .a projectile wherein means are provided for. exploding the pro.- jectile upon impact of the projectile with a target or when the spin of the projectile has decreased to a prede: termined value.

Another object is to provide a novel and eifective fuze in which a normally wound resilient member is provided for delaying arming of the fuze until the projectile has been fired from a gun and traveled a predetermined dis: tance beyond the muzzle thereof.

Still another object is to provide means including a Ne.-

this invention will be readily appreciated as the same be:

Batented Apr. 30, 1957 i comes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

\Fig. l is a central longitudinal section view of the device of the present invention in accordance with the preferred embodiment thereof, the mechanism being shown in an unarmed or safe condition;

Fig. 2 is a view similar to Fig. l with the mechanism in an armed condition;

Fig. 3 is a cross sectional view taken on the line 3-3 of Fig. l; and

Fig. 4 is fragmentary sectional view of an alternate arrangement of the device of Fig. 1.

Referring now to the drawings, and more particularly to Fig.1, thereof, the fuze is generally indicated by the reference and comprises a. nose member 11 of conical contour and composed of any material suitable for the purpose such, for example, as steel or the like. The member 11 is provided with a recess 12 threaded as at 13 for threaded engagement with a casing 14, the recess 12 being in communication with a bore 15 formed in the member 11 and extending therethrough.

'Slideably arranged within the bore 15 is a firing pin generally indicated by the numeral 16 and comprising an elongated shaft 17 threaded as at 18 and having a striker 19 formed thereon.

Rotatably supported on the firing pin and disposed within the recess 12 is an inertial rotor or weight 21 having a bore 22 formed therein of greater diameter than the threaded pontion 18 of the firing pin. Formed on the rotor 21 and arranged within the bore 22 therein is a threaded portion 23, in engagement with the threaded portion 18 on the firing pin 16 and consisting of a comparatively small number of threads. By this arrangement it will be obvious that upon impact of the missile with a target the relatively small threaded portion on the inertial member will be readily sheared in response to the impact whereupon the firing pin is forcibly driven to a firing position. As shown on Figs. 1 and 2 the firing pin is slideably maintained within the nose 11 by a pin secured to the firing pin and disposed within a groove 40 formed in the nose.

As more clearly shown on Fig. 3 the Negator type spring 24 is wound about the rotor 21, the inner convolution of the spring is secured to the inertial mass as at 25, the outer convolution thereof being secured to the nose 11 as at 26, the spring being adapted to rotate the inertial mass as the spring is unwound in response to centrifugal force.

As shown on Fig. 1 a normally locked arming rotor generally indicated by the reference character 29 and comprising a circular body 31 is rotatably supported within a cage 32 disposed in a recess 33 formed in the casing 11. The arming member is locked in an initial safe position by the striker 19 disposed in a recess 34 formed in the arming member and extending through an aperture 30 formed in the cage 32. The arming rotor is adapted to be rotated to an armed position in re sponse to centrifugal force when the firing pin is moved sufiiciently in response to the rotation of the mass 21 to cause the striker 19 thereon to be moved out of engagement with the recess 34. When this occurs the fuze is in an armed condition with the firing pin extended and in alignment with the sensitive detonator 35 arranged within the arming rotor; It will be understood, however, that the arming rotor may be locked in an armed position in any suitable manner such, for example, as by a conventional spring actuated detent. In the even-t that the projectile fails to strike a target and the rate of spin thereof decreases to a substantially null degree, centrifugal force acting on the spring is overcome by the elastic force of the spring and thus the spring assumes its original condition Fig. 1. As the spring moves to its original condition the striker 19 is moved into firing engagement with the sensitive detonator as the firing pin is actuated to a firing position as heretofore set forth.

The Negator spring is especially constructed and has the peculiar characteristic and tendency to remain coiled, however, upon unwinding thereof in response to centrifugal force the spring will remain unwound until the rate of spin of the projectile becomes substantially reduced. When this occurs the spring will assume its original condition, i. e., tightly wound around the inertial rotor.

Secured to the nose member 11 is a windshield 36, the windshield being secured thereto in any suitable manner such, for example, as by a flange 37 crimped into engagement with the end portion of the member 11 as at 33. The windshield is provided with a crushed impact end 39 spaced from the outer end of the nose 11. When the fuse is in an armed condition, the firing pin is in abutting engagement with the impact end 39 of the windshield Fig. 2, and thus upon impact of the projectile with the target the end 39 is crushed in response thereto whereupon the firing pin is moved sufliciently thereby to cause the striker thereon to be moved into firing engagement with the detonator.

Disposed within the recess 33 is a support 41 comprising a plate 42 arranged in abutting engagement with the cage 32 and having a centrally disposed bore 43 formed therein. Arranged within the bore 43 and normally out of alignment with the detonator 35 .is a lead-in charge 44, the lead-in charge being in engagement with a booster charge 45 disposed within a recess 46 formed in the casing 14 and maintained therein by a cap 47.

When the fuze is armed, Fig. 2, it will be noted that the firing pin 16, detonator 35 and 'lead-incharge 44 are in alignment with respect to each other whereupon the fuze will function to explode the projectile upon impact thereof with the target or when the spring forces overcome centrifugal forces in response to a substantial decrease in the rate of spin of-the projectile in the event that the projectile fails to strike a target.

As shown on Fig. 4, a flexible mass 49 is wound around the inertial weight 21 in lieu of the Negator spring 24, it being understood, however, that one end ofthe mass is secured to the casing 14, and the other end thereof is secured to the weight 21. In this arrangement the inertial weight has formed thereon a hub 51 around which is arranged a normally unwound clock spring 52, the spring being secured to the hub and casing in any suitable manner. By this arrangement it will be apparent that as the projectile spins along it trajectory the flexible mass moves outwardly and unwinds in response to centrifugal force and thus by reason of the threaded connection between the weight and firing pin the pin is moved to a release position. When this occurs the arming rotor is released for rotation to an armed position by centrifugal force. During rotation of the inertial member and the flexible mass the normally unwound spring is wound sufiiciently to move the firing pin into firing engagement with the detonator when the rate of spin of the projectile has decreased to a degree whereby the elastic force of the spring overcomes centrifugal force acting on the mass and thus the explosion of the projectile will occur in the event that the projectile fails to strike the target, the device also being adapted to function to explode the projectile upon impact thereof'jwith a target.

In view of the foregoing it will be evident that delayed arming is obtained by virtue of the inertia of the inertial mass or rotor. However, if desired, the time delay period may be regulated by varying the moment of inertia of the inertial mass, by varying the; number of revolutions required to actuate the inertial mass a predetermined distance by varying the mass and resilient characteristics of the spring or by varying the operating diameters of the spring. Furthermore, the present invention contemplates the provision of a fuze in which new and improved means are provided for delaying the arming thereof until the projectile has been fired from a 'gun and traveleda safe distance beyond the muzzle thereofand in which means controlled by centrifugal force actuates the fuze to an armed condition as the projectile travels along its trajectory whereupon the fuze may be actuated to explode the projectile upon impact of the projectile with an aircraft in flight or when the spin of the projectile has decreased to a relatively low value in the event that the projectile fails to strike the target. Furthermore, while the device of the present invention has been specifically described in connection with an ordnance missile it will be understood, however, if desired, the device may be advantageously employed as a speed regulator or control element for use in rotating devices and mechanisms.

Obviously many modifications and variations of the present inventiontare possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise that as specifically described.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a fuze for a rotative projectile, in combination, a fuze casing, a firing pin slideably arranged within said casing for movement axially from an initial position to a moved position, a threaded portion on said firing pin, a centrifugally actuated arming rotor releasably locked in an initial safe position by said firing pin and released thereby for rotation to an armed position as the firing pin is moved to said moved position, a detonator arranged within said arming rotor and moved into alignment with said firing pin as the arming rotor moves to said armed position, an inertial weight having a shearable threaded portion in engagement with the threaded portion on said firing pin and rotatably supported on said firing pin for moving said firing pin axially to said moved position when the weight has been rotated a predetermined amount, a normally tightly wound resilient member secured to said casing and inertial weight for rotating said weight said predetermined amount as the resilient member is unwound and expanded in response to centrifugal force, a guide element carried by said firing pin in engagement with said casing for preventing rotation of the firing pin as said inertial weight is rotated a crushable nose on said fuze in engagement with said firing pin when the pin 7 is in said firing position and crushed in response to impact of the projectile with a target for severing said threaded portion on said weight and forcibly driving the firing pin into firing engagement with said detonator, and explosive means fired by said detonator for exploding said projectile upon said impact.

2. In a fuze for a rotating projectile, in combination,

a fuze casing, an inertial mass rotatably supported within said casing, a shearable threaded portion on said mass, a firing pin disposed within the casing in engagement with said shearable threaded portion and movable axially from an initial safe position to a moved position by said mass as the mass is rotated, a centrifugally actuated arming rotor releasably locked in said initial safe position by the firing pin and released thereby for rotation to said armed position as the firing pin is actuated to said moved position, a normally tightly wound resilient member secured to said casing and mass for maintaining the firing pin releasably locked to said rotor and for rotating said mass as the resilient member is unwound and expanded in response to centrifugal force, a crushable nose carried by said fuze for forcibly moving the firing pin and severing said threaded portion upon impact of the projectile with a target, and explosive means mounted in said rotor and fired by the firing pin for exploding the projectile.

3. In a fuze for a rotating projectile, in combination, a fuze casing having a slot formed therein, a rotatable inertial mass arranged within said casing on the axis of rotation of said projectile and having a centrally disposed bore therethrough, a shearable threaded portion formed on said mass within said bore, a firing pin having a threaded portion disposed with said bore in engagement with said shearable threaded portion and of less diameter than said bore whereby the firing pin is actuated to a firing position upon impact of the projectile with a target, a normally tightly wound resilient member secured to said mass and the casing for rotating said mass and moving the firing pin axially to an armed position as the resilient member is unwound and expanded in response to centrifugal force, a guide pin on said firing pin in engagement with said slot for preventing rotation of the firing pin as the mass is rotated, and a crushable nose secured to said casing and crushed in response to said impact for moving said firing pin with sufiicient force to sever said shearable threaded portion as the firing pin is actuated to said firing position.

References Cited in the file of this patent UNITED STATES PATENTS 2,446,019 Nichols July 27, 1948 4 2,458,405 Nichols Jan. 4, 1949 FOREIGN PATENTS 9,503 Great Britain of 1891 11,874 Great Britain May 18, 1912 

